Resist composition and patterning process

Abstract

A resist composition is provided comprising a base polymer containing an iodized polymer, and an acid generator containing a sulfonium salt and / or iodonium salt of iodized benzene ring-containing fluorosulfonic acid. When processed by lithography, the resist composition exhibits a high sensitivity, low LWR and improved CDU independent of whether it is of positive tone or negative tone.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application Nos. 2017-183795 and 2018-054115 filed in Japan on Sep. 25, 2017 and Mar. 22, 2018, respectively, the entire contents of which are hereby incorporated by reference.TECHNICAL FIELD[0002]This invention relates to a resist composition comprising a polymer containing iodized recurring units and a sulfonium or iodonium salt of iodized fluorosulfonic acid, and a patterning process using the composition.BACKGROUND ART[0003]To meet the demand for higher integration density and operating speed of LSIs, the effort to reduce the pattern rule is in rapid progress. The logic devices used in smart phones drive forward the miniaturization technology. Logic devices of 10-nm node are manufactured in a large scale using a multi-patterning lithography process based on ArF lithography.[0004]In the application of lithography to next 7-nm or 5-nm node devices, the in...

AI Technical Summary

Benefits of technology

[0031]A resist composition comprising an iodized polymer and an acid generator capable of generating an iodized benzene ring-containing fluorosulfonic acid has the advantage of controlled acid diffusion due to the high atomic weight of iodine. Since iodine is highly absorptive to EUV of wavelength 13.5 nm, it effectively generates secondary electrons during exposure. This contributes to a higher sensitivity than a combination of an iodized polymer with an acid generator capable of generating an iodine-free fluorosulfonic acid. Thus, a resist material having a high sensitivity, low LWR and improved CDU may be designed.

Problems solved by technology

In the application of lithography to next 7-nm or 5-nm node devices, the increased expense and overlay accuracy of multi-patterning lithography become tangible.

In the EUV lithography, the phenomenon that the edge roughness (LWR) of line patterns or the critical dimension uniformity (CDU) of hole patterns is degraded by a variation of photon number is considered a problem.

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